Apparatus for compaction of formed sheet for improved properties



July7, 1964 HORNBOSTEL 3, 0,2 4 1 APPARATUS FOR COMPACTION OFFORMEDSHEET FOR IMPROVED PROPERTIES Filed May 2. 1960 wwwwww United StatesPatent 3,140,224 APPARATUS FOR COMPACTION OF FORMED SHEET FOR IMPROVEDPROPERTIES Lloyd Hornbostel, Beloit, Wis., assignor to Beloit IronWorks, Beloit, Wis., a corporation of Wisconsin Filed May 2, 1960, Ser.No. 26,364 3 Claims. (Cl. 162-348) This invention relates to theproduction of paper and is more particularly directed to improvedmethods and means for compaction of formed paper webs and related webmaterials.

Heretofore it has been customary in the prior art to employ Fourdriniermachines having wires made of an annealed copper, brass, or a Phosphorbronze, very finely drawn and woven into a wire mesh web. The mesh ofthe web is normally determined by the particular end product to beformed on the paper making machine.

It has been generally thought that the Fourdrinier wire must, ofnecessity, be constructed of metal wire and that because of the inherentlimitations in such Wire, certain operational safeguards had to be takenin order to form acceptable sheets or mats on the wire. For example,bruises or kinks in the wire soon cause them to Wear or break through,thereby seriously shortening their use life. Emphasis has been given inrecent years to improving the formation of the paper sheet or mat on theFourdrinier wire and, for this purpose, shakers, deckles, tube or tablerolls, suction boxes, dandy rolls, and improved couch rolls have beendesigned with the view toward obtaining better quality paper sheet ormat on the wire. Thus, as a result of this common belief that theFourdrinier wire must be constructed of metal wire which imposestringent operating conditions, all previous attempts to improve thecharacteristics of the paper on the wire have taken the form ofindependent apparatus acting through or on the wire and paper mat orweb. As far as I am aware, no attempts have been made to improve thecharacteristics of (the web by changing the characteristics of theFourdrinier wire.

By employment of my invention, wherein a Fourdrinier wire, constructedof a material having elastic properties preferably comprising a fabricmatrix woven of longitudinally extendingplastic yarns or filaments andpreferably with transverse metal wire for the Weft or shoot elements, isappropriately stretched over a breast and a couch roll, and the tensionthereon is progressively reduced at the couch roll, I provide simple andeffective means for pro ducing paper webs and related web materialscompacted on the forming wire to a degree heretofore consideredunobtainable in the art having improved strength, flexibility andelongation characteristics.

It is therefore an object of the present invention to provide means forimproving the properties of paper web and related web materials on papermaking machines.

It is another object of the present invention to provide improved meansfor compacting paper web and related web materials.

' It is another object of the present invention to provide means forimproving the characteristics of paper web and related web materials bycontrolled contraction of an elastic Fourdrinier Wire.

A still further object of the present invention is to produce paper websand related web materials having strength flexibility and elongationcharacteristics heretofore considered unobtainable on Fourdriniermachines.

It is still another object of the present invention to provide a new andimproved Fourdrinier wire permitting compaction of paper web and relatedweb material there- It is another object of the present invention toprovide an elastic Fourdrinier wire consisting of a fabric woven3,14%,224 Patented July 7, 1964 with longitudinally extending plasticyarn or filaments and with metal wires as transverse weft or shoots.

It is a further object of the present invention to provide a new andnovel method of compacting paper Web and related web materials on aFourdrinier machine.

Another object of the present invention is to provide means forimproving the characteristics of paper web and related web materials byfiber compaction which are simple and compact in construction, andeflicient and high speed in operation.

These and other objects, features and advantages of the presentinvention will become more apparent upon a careful consideration of thefollowing detailed description, when taken in conjunction with theaccompanying drawing illustrating preferred embodiments of the conceptsof my invention, wherein like reference characters and numerals refer tolike or corresponding parts throughout the several views.

On the drawings:

FIGURE 1 is a partially diagrammatic view in side elevation of apparatusfound useful in the practice of my invention;

FIGURE 2 is a partially diagrammatic view illustrating anotherembodiment of apparatus found useful in the practice of my invention;and

FIGURE 3 is an enlarged fragmentary view illustrating a Fourdrinier wireconstructed in accordance with the principles of the present invention.

. Briefly stated, the present invention contemplates a Fourdrinier wirehaving elastic properties constructed preferably of a fabric woven oflongitudinal plastic yarn or filaments and transverse metal wires forthe weft or shoot wires which traverses a breast roll and a couch rolland carries the paper web or related web material while the wire isstretched under a tension provided by means controlling operationalspeed of the breast roll as a function of the operational speed of thecouch roll.

With the elastic Fourdrinier wire under longitudinal tension andelongation, the formation of the paper web or related web material iscompleted near the dry end of the Fourdrinier machine where the fluidstate of the mat is reduced and the mat transformed into a water filledfiber network web. In this state, the mat or Web has an inherent degreeof plasticity and is capable of resisting shear forces. At the dry endof the Fourdrinier machine the mat or web passes over the drivingsuction couch roll where the tension in the Fourdrinier wire isprogressively reduced to the minimum or base tension, and the web,constrained by the suction pressure forces of the couch roll, is therebycorrespondingly contracted in a plane parallel to width of the wire. Thecontraction forces within the web itself, cooperating with the suctionpressure forces of the couch roll, tend to crowd the fibers and fibrilsof the paper mat closer together thereby enhancing the desiredmechanical entanglement of the paper web or related web material. Inaddition the compression of the web and entanglement of the fibers andfibrils of the Web assist in removing additional water at the couchroll. The paper web or related web material resulting from suchtreatment has an increased strength and marked flexibility not found inpaper webs formed on the conventional metal wire Fourdrinier machine.

The resulting paper web or related Web material is not comparable tocrepe paper but is a paper substantially as smooth after having beencompacted as before. In other words, the compaction of the Web by thepractice of my invention produces a resulting paper web or related webproduct having the same desirable characteristics of paper formed on theconventional metal Fourdrinier wire but with increased strength,compactness, and elasticity flexibility.

Apparatus found useful in the practice of my inven- I. tion, as appearsin FIG. 1, includes a conventional pulp or stock formation device 6 fromwhich the pulp is fed onto a Fourdrinier wire 7 in the form of anendless loop which traverses a breast roll 8, a driven couch roll 9,which is preferably a suction couch roll, as shown, and a plurality ofguide rolls 10 through a. A plurality of conventional suction boxes 16are provided for the extraction of water from the web through the wireaiding in web compaction.

Tension is applied to the top side of the wire carrying the mat Mlongitudinally in the direction of travel of the web by providingtension control means. The degree of tension applied to the elastic wirewill, of course, depend upon the end product desired. For instance, forboard as compared with lightweight paper, the tension will becomparatively greater. Means to provide wire tension may take the formof brake means 17 controlling operation of the breast roll 8. The brakemeans 17 may be connected to the main drive shaft of the couch rolldrive means 18 by a differential gear arrangement indicated by thenumeral 18a. Alternately, the tension control may be provided byelectrical drive means employing the well known regenerative brakingmethods or, by a simple gear arrangement connecting the breast roll tothe main couch drive to provide the desired degree of roll speeddifferential required for the particular application involved.

It will be noted from prior Hornbostel et al. US. Patent No. 2,992,965that, even with no brake on the breast roll or with substantially notension change in the wire at the breast roll, there is a minute amountof stretching of the wire between the breast roll and the couch rollprimarily as the tension in the wire changes when it is driven under theso-called loaded conditions, i.e., with a web forming thereon over thesuction boxes. This prior patent teaches that this minute amount ofstretching is significant in that it should not be eliminated by drivingthe normally loaded wire at the couch roll because this causes a verysmall amount of decrease in the tensioned wire to take place while thewire is in contact with the suction couch roll, thus causing the wirewear. The stretching and the consequent reduction in stretching orelongation of the wire described in this patent are significant factorsinsofar as Wire wear is concerned, but they are practicallyimperceptible for most other purposes in the operation of the papermachine and they do not constitute the type of stretching or elongationof the wire that is contemplated in the present invention. This is sobecause the present invention positively calls for brake means 17controlling the operation of the breast roll, or equivalent means whichwill actually cause a deliberate and functional stretching of the wireto the extent that it is functionally elongated for the purposes setforth in greather detail in this specification. As is pointed out in theprior patent the nominal operating conditions of paper machines underso-called normal load conditions do not call for any braking meansfunctioning in conjunction with the breast roll to deliberately createadditional wire elongation and/ or tensioning which results instretching. The prior patent thus describes the so-called conventionalconditions of a loaded paper machine being driven by rolls in aparticular manner described in said prior patent. The instant invention,in contrast, calls positively for brake means 17 or their equivalent toeffect a substantial elongation or wire stretching between the brakedbreast roll and the driven couch roll, with a consequent and subsequentcontraction of the elongated or stretched wire that is again ofsubstantial and functional significance for the purposes described indetail herein.

As aforesaid, the Fourdrinier Wire 7 in the form of an endless loop maybe constructed of any material having elastic properties which willprovide the necessary stretch elongation required for compacting the matthereon. The wire is preferably constructed of a plastic materialcomprising a pervious fabric having longitudinal plastic yarn orfilaments extending in the direction of travel of the web and with metalwires as the transverse weft or shoot wires.

The non-metallic fabric filler or shoots employed, will, of course, bechosen on the basis of its adaptability for the paper making purposesinvolved. The longitudinal cords of the wire are preferably constructedof yarn or filament having elastic properties, such as the natural andsynthetic plastics from which textile fibers having elastic memories areprepared or possibly a resilient cotton yarn.

The transverse weft or shoot fibers or filaments of the wire, i.e.,those transverse to the direction of travel of the web, may also beconstructed of similar material having elastic properties; however, Iprefer to employ a metal wire for such transverse cords or filamentssince improved transverse stability of the wire is obtained whereas awire consisting of both longitudinal and transverse materials havingelastic properties would tend to reduce in width as the longitudinalelongation occurs. It will be noted that by employment of the plasticmaterial in the Fourdrinier wire a lighter weight wire may beconstructed.

A preferred form of wire is shown in FIG. 3 wherein the longitudinalyarn or filaments 7a (arrow) consist of plastic material having thedesired elastic properties and the transverse yarn or filaments 7b areconstructed or metal wire. The elastic forming wire itself is of suchstrength as to withstand the tension applied thereto and to permitcontinued application of suction forces there through.

Thus with the elastic Fourdrinier wire placed under a tension sufficientto stretch it by employment of the brake means 17 for breast roll 8,paper stock may be fed from the forming apparatus 6 onto the wire 7. Thematting stock traverses the suction boxes 16 while on the stretched wireand is then led over couch roll 9. Couch roll 9 is preferably a suctioncouch roll, and, as the matting stock passes over the suction couch rollto be removed, as for example, by a transfer felt (not shown), thetension on the elastic wire is gradually reduced to the minimum or basetension which exists on the bottom side of the wire as it traversesguide roll 10 through 15a. The formation therefore of the web takesplace on the wire while it is in the stretched condition and iscompleted to an extent before the passage thereof over driving suctioncouch roll 9.

As the tension on the wire is progressively reduced the fibers of theweb are distorted by contraction and to a degree the distorted fibersare forced into the void spaces within the paper web thereby entanglingthe fibers and fibrils. The inherent adhesion of the fibers and fibrilsof the web causes them to further entangle into a coherent compact mass.The suction couch roll, by withdrawing water from the paper web, assistsin the compression and compaction of the fibers and fibrils not only bywithdrawing water from the web but also by holding the web in suctionengagement with the Wire.

The compressed web is then transferred from the Wire at a pointpreferably where the wire tension has been reduced to the minimum orbase tension to a felt (not shown). It has been our experience thatwhile open draw operation results in a paper product having greaterstrength and flexibility than web made on conventional Fourdrinierwires, it is preferabe to remove the web from the elastic wire byemployment of a suction pickup roll to maintain the contraction of theweb at the optimum level.

After having been transferred to the transfer felt, the natural andinherent adherence of the compressed fibers and fibrils maintain the webin the compacted condition.

It will be appreciated that the differences in local or spot densitynormally encountered with paper webs formed on a conventionalFourdrinier wire are not found in the product made in accordance withthe present invention. Thus a paper web having a substantially uniformdensity throughout may be prepared which has enhanced desirablecharacteristics for such applications as printing, coating and glossing.Furthermore, the bulk or thickness of the web is not materially reducedas a result of the contraction thereof. The bulk or thickness of the webneed not be materially increased, since the web compaction may becontrolled by regulating wire tension release. Paper web products madein accordance with my invention exhibit a marked increase in elasticityand resiliency in addition to increased strength, flexibility andelongation. Thus end products, such as board, bag, tissue, creping andthe like may be prepared from the compacted web material obtained by thepractice of my invention.

The particular tension applied to the elastic wire and consequently thespeed differentials between breast roll 8 and couch roll 9 will dependprimarily upon the type of paper web being formed on the wire. Inaddition to control of wire tension, the rate of reduction in tension atthe couch roll will depend similarly upon the end product desired andthe compaction thereof necessary to achieve the desired characteristicsof the end product.

As appears in FIG. 2, an alternate embodiment of apparatus found usefulin the practice of my invention comprises a standard stock formationapparatus 6 and the elastic Fourdrinier wire 7 traversing breast roll 8and couch roll 9, which is preferably of the suction type. Guide rolls10 through a and suction boxes 16 may also be provided in the usualmanner. Brake means 17 are provided, and the tension applied to the wire7 by breast roll 8 under the influence of brake means 17 through gearingapparatus 18a connected to the couch roll 9 for maintaining the desireddegree of speed differential between breast roll 8 and couch roll 9. Asuction pickup roll 22 is shown for transferring the web aftercontraction there- 'of to appropriate transfer means, such as a transferfelt 23.

Brake means 17 for applying tension on the forming wire are employed forregulating the differential speed required between couch roll 9 andbreast roll 8 to achieve the desired stretch on the web forming wire 7.

In addition, means may be employed to assist in reducing the amount ofwater in the mat or paper web being formed on the wire 7. Such means maytake the form of a wire 24, similar in construction and operation towire 7, which, as shown, traverses the roll 25 and driven roll 26. Roll26 may be driven as by drive means 27, and the tension on the top wire24 may be controlled by regulating the speeds of roll 25 by brake means28 connected to the drive means 27 of driven roll 26 through adifferential gear arrangement 29 which may be similar in constructionand operation to gear means 18a.

To prevent relative slippage between top wire 24 and forming wire 7which would otherwise occur within the web material if the surfacespeeds of wires 7 and 24 were different while under tension, speedequalization of the respective driven and driving rolls of wires 7 and24 may be obtained by coupling drive means 18 and 27, thus synchronizingtheir speeds to thereby regulate the tension applied to wires 7 and 24through the action of brake means 17 and 28 coupled to the respectivedrive means 17 and 27 through the gearings 18a and 29 respectively. Bythus coupling the drive rolls of wires 7 and 24, the speeds of the wireswill be identical, thereby preventing relative web slippage therebetweenand the wires 7 and 24 will be traveling with the same surface speeds.

As the forming web, pressed by wire 7 against wire 24, reaches thedriven roll 26, a substantial amount of the water therein has beenremoved and the natural adhesion of the fibers in the web tend to holdthe mat in an integral entanglement. By positioning the suction boxes16, as shown, the suction forces, acting on the web as it leaves contactwith wire 24 adjacent the driven roll 26, tend to initially crowd thefibers closer together in an entangled condition and further assist inremoving additional water from the web. The web then passes over thedriving suction couch roll 9 where the tension on the wire is progressively reduced, and, the wire, in contracting, causes a correspondingcontraction of the web distorting the fibers and fibrils of the webstill further, and, the thus distorted fibers and fibrils are forcedfurther into the void spaces within the paper web thereby funthermechanically entangling the fibers and fibrils.

The compressed web is then transferred from the wire to the transferfelt 23 at a point of reduced wire tension, preferably where the wiretension has been reduced to the minimum or base tension to the transferfelt 23.

The natural and inherent adherence of the compressed fibers and fibrilswill maintain the web in the compacted condition after having beentransferred to the transfer felt.

Thus by employment of the top wire, the amount of water in the web onthe forming wire may be considerably reduced, and thereby subsequenttreatment of the web by specialized apparatus on the paper makingmachine facilitated, depending upon the particular end product desired.

Although various minor modifications might be suggested by those versedin the art, it should be understood that I wish to embody within thescope of the patent warranted hereon all such embodiments as reasonablyand properly come within the scope of my contribution to the art.

I claim as my invention:

1. Apparatus for compacting paper Web material an related web materialson a Fourdrinier machine comprising: an elastic Fourdrinier wire adaptedto traverse a breast roll spaced-apart from a driven couch roll; suctionmeans intermediate said breast roll and said couch roll whereby watermay be withdrawn through said wire from a web material being formedthereon; means for regulating the relative speeds of said breast rolland said couch roll whereby said breast roll applies a tension on saidWire stretching said wire in the direction of wire travel to said couchroll, said wire contracting during its contact with and travel over saidcouch roll in the direction of wire travel to said breast roll wherebyweb forming slurry deposited on said wire while it is in a stretchedcondition is compacted while said wire is contracting; a second elasticwire adapted to traverse at least two wire support means positionedabove said elastic Fourdrinier wire for pressing a web being formed onsaid Fourdrinier wire to thereby remove water therefrom, and means tocontrol the surface speed of said second wire, said speed regulatingmeans for the breast and couch rolls including braking means operativelyconnected to said breast roll whereby the breast roll speed differentialrelative to that of the wire and the couch roll is positively maintainedand stretching of the wire as a consequence is positively controlled andthe amount of stretching is over and beyond the nominal wire stretchinginherent in the driving of wire under conditions of load otherwisespecified in this claim.

2. Apparatus for compacting paper web material and related web materialson a Fourdrinier machine comprising an elongatable Fourdrinier wireadapted to tra verse a breast roll spaced apart from a driven couchroll, suction means intermediate said breast roll and said couch rollwhereby water may be withdrawn through said wire from a web materialbeing formed thereon, brake means for sufficient positive and materialbraking of said breast roll to substantially reduce the speed of saidbreast roll below that of said couch roll and to sufliciently tensionsaid wire to cause a substantial elongation of said wire in a directionof wire travel to said couch roll with said wire being adapted tocontract during its contact with and travel over said couch roll in thedirection of wire travel returning back to said breast roll, whereby webforming slurry deposited on said wire while it is in the aforesaidelongated condition between the breast roll and couch roll is compactedwhile said wire is contracting.

3. Apparatus for compacting paper web material and related web materialson a Fourdrinier machine comprising an elongatable Fourdrinier wireadapted to traverse a breast roll spaced apart from a driven couch roll,suction means intermediate said breast roll and said couch roll wherebywater may be withdrawn through said wire from a web material beingformed thereon, positive drive means operatively connected with theforming wire to drive the same in a return run back from the couch rollto the breast roll and to maintain the couch roll at a predeterminedspeed, brake means for sulficient positive and material braking of saidbreast roll to substantially reduce the speed of said breast roll belowthat of said couch roll and to sufiiciently increase tension in the wireabove any tension increase in the Wire caused by moving the wire withthe web thereon over said suction means and to said couch roll to causea substantial elongation of said Wire in the aforesaid direction of wiretravel toward said couch roll with said wire being adapted to contractduring its travel over the couch roll in association with the aforesaidpositive drive means, with such contraction occurring in the directionof wire travel in the aforesaid return run from the couch roll to thebreast roll, whereby web forming slurry deposited on the Wire While itis in an elongated condition is compacted while said wire is undergoingthe aforesaid contraction, and means for removing the contracted webthus formed from the contracted forming wire.

References Cited in the file of this patent UNITED STATES PATENTS1,410,856 Warburton Mar. 28, 1922 2,622,492 Goodwillie Dec. 23, 19522,881,670 Thomas Apr. 14, 1959 2,888,378 Maguire May 26, 1959 2,903,021Holden et a1 Sept. 8, 1959 2,969,581 Bischolf Jan. 31, 1961 2,992,965Hornbostel et al July 18, 1961 FOREIGN PATENTS 715,522 Great BritainSept. 15, 1954 OTHER REFERENCES Collins: Shafting, Pulleys, Belting andRope Transmission, Hill Publishing (10., New York, 1908, pp. 106, 107.Copy in Sci. Lib.

Flather: The Transmission of Power, University Press, University ofMinnesota, Minneapolis, 1908, pp. 5-7.

1. APPARATUS FOR COMPACTING PAPER WEB MATERIAL AND RELATED WEB MATERIALSON FOURDRINIER MACHINE COMPRISING: AN ELASTIC FOURDRINIER WIRE ADAPTEDTO TRAVERSE A BREAST ROLL SPACED-APART FROM A DRIVEN COUCH ROLL; SUCTIONMEANS INTERMEDIATE SAID BREAST ROLL AND SAID COUCH ROLL WHEREBY WATERMAY BE WITHDRAWN THROUGH SAID WIRE FROM A WEB MATERIAL BEING FORMEDTHEREON; MEANS FOR REGULATING THE RELATIVE SPEEDS OF SAID BREAST ROLLAND SAID COUCH ROLL WHEREBY SAID BREAST ROLL APPLIES TO A TENSION ONSAID WIRE STRETCHING SAID WIRE IN THE DIRECTION OF WIRE TRAVEL TO SAIDCOUCH ROLL, SAID WIRE CONTRACTING DURING IN CONTACT WITH AND TRAVEL OVERSAID COUCH ROLL IN THE DIRECTION OF WIRE TRAVEL TO SAID BREAST ROLLWHEREBY WEB FORMING SLURRY DEPOSITED ON SAID WIRE WHILE IT IS IN ASTRETCHED CONDITION IS COMPACTED WHILE SAID WIRE IS CONTRACTING A SECONDELASTIC WIRE ADOPTED TO TRAVERSE AT LEAST TWO WIRE SUPPORT MEANSPOSITIONED ABOVE SAID ELASTIC FOURDRINIER WIRE FOR PRESSING A WEB BEINGFORMED ON SAID FOURDRINIER WIRE TO THEREBY REMOVE WATER THEREFROM, ANDMEANS TO CONTROL THE SURFACE SPEED OF SAID SECOND WIRE, SAID SPEEDREGULATING MEANS FOR THE BREAST AND COUCH ROLLS INCLUDING BRAKING MEANSOPERATIVELY CONNECTED TO SAID BREAST ROLL WHEREBY THE BREAST ROLL SPEEDDIFFERENTIAL RELATIVE TO THAT OF THE WIRE AND THE COUCH ROLL ISPOSITIVELY MAINTAINED AND STRETCHING OF THE WIRE AS A CONSEQUENCE ISPOSITIVELY CONTROLLED AND THE AMOUNT OF STRETCHING IS OVER AND BEYONDTHE NOMINAL WIRE STRETCHING INHERENT IN THE DRIVING OF WIRE UNDERCONDITIONS OF LOAD OTHERWISE SPECIFIED IN THIS CLAIM.